study of urban population attitudes towards various wastewater reuse options: israel as a case study
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Journal of Environmental Management 81 (2006) 360–370
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Study of urban population attitudes towards various wastewaterreuse options: Israel as a case study
Eran Friedlera,�, Ori Lahava, Hagar Jizhakib, Tali Lahavc
aFaculty of Civil and Environmental Engineering, Technion, Haifa, 32000, IsraelbFaculty of Sociology and Anthropology, Emek Yezreel College, Israel
cSchool of Social Work, Hebrew University, Jerusalem, Israel
Received 27 December 2004; received in revised form 29 September 2005; accepted 1 November 2005
Available online 29 March 2006
Abstract
This paper summarizes the findings of a survey (256 participants) conducted to determine the attitude of the Israeli urban public
towards various urban water reuse options. Israel is known for its long and successful agricultural water reuse scheme, but to date no
large-scale urban reuse projects have been implemented. The survey included 21 reuse options, which were clustered into three reuse
categories, namely: low, medium, and high contact levels. Results show that a high proportion of the participants supported medium
contact reuse options such as sidewalk landscaping (95%), domestic WC flushing (85%) and firefighting (96%). Higher contact reuse
options such as domestic laundry (38%), preserved food (13%), and potable aquifer recharge (11%) found much lesser support. Less
than expected support was found for low contact reuse options with 86% for field crop irrigation, 62% for aquifer recharge for
agricultural irrigation, and as low as 49% for orchard irrigation. This low support is surprising, since all three options have been
practiced on a large scale for over three decades in Israel without any adverse effects to the public. No correlation was found between any
biographical characteristic examined (education, gender, income, marital status, having young children, and age) and support for
medium contact options. For the medium contact options, the results suggest that perceived financial gain (individual and/or communal)
and positive public opinion enhances support, while perceived health effects negatively affects the degree of support. Technology, trust in
authorities and awareness of water and environmental issues were found to not have a significant effect on support for medium contact
reuse options. Analyzing the four possible reasons for support given by participants who identified themselves as supporters of
wastewater reuse revealed that the most important reason for support was ‘‘water saving’’, followed by ‘‘minimization of importing water
from abroad’’. These were followed by ‘‘infrastructure cost saving’’ together with ‘‘environmental improvement’’.
r 2006 Elsevier Ltd. All rights reserved.
Keywords: Wastewater reuse; Public awareness; Public perception; Urban reuse
1. Introduction
Successful implementation of a wastewater reuse projectdepends not only on its economic and environmentalfeasibility, but mainly on the support of the general public,who, ultimately, pays for, and might be affected by thereuse project. Irrespective of scientific and engineering-based considerations, public opposition has the potential tocause wastewater reuse projects to fail, before, during, or
e front matter r 2006 Elsevier Ltd. All rights reserved.
nvman.2005.11.013
ing author. Tel.: +972 4 8292633; fax: +972 4 8228898.
esses: [email protected] (E. Friedler),
ion.ac.il (O. Lahav), [email protected] (H. Jizhaki),
ail.com (T. Lahav).
after their execution. Reuse schemes may face publicopposition resulting from a combination of prejudicedbeliefs, fear, attitudes, lack of knowledge and generaldistrust, which, on the whole, is often not unjustified,judging by the frequent (and highly publicized) failures ofwastewater treatment facilities worldwide (Wegner-Gwidt,1991; Jeffrey and Temple, 1999).Despite being a somewhat problematic tool, results from
several surveys on public attitudes toward wastewater reuseoptions have been published, the data collected particularlyin the US, Western Europe and Australia. Much lessinformation is available regarding the attitude toward theissue in other regions, and under different environmentaland climatic conditions.
ARTICLE IN PRESSE. Friedler et al. / Journal of Environmental Management 81 (2006) 360–370 361
Reviewing the literature, published public attitudesurveys can be roughly divided to three categories, eachdealing with a different situation: The first categoryconsists of studies that attempt to establish the ‘‘general’’attitude toward water reuse by asking the public wideranging questions, not necessarily attached to a specific,imminent reuse scheme. To the second category belongstudies that seek public opinion on actual, forthcomingwater reuse projects. The third group consists of studiesthat examine public attitude in places where reuse schemeshave already been put in place.
Two clear conclusions can be drawn from the firstcategory studies (to which most of the studies belong): thefirst is that in the places that were surveyed a large majorityof the public support water reuse as a concept; the second isthat public support for reuse clearly decreases as the degreeof contact with the reclaimed water increases. For example:based on nine different surveys performed in the UnitedStates, Bruvold (1984) showed negative correlation be-tween support for water reuse and the degree of contact; inAustralia, 97% and 96% of the public supported waste-water reuse for irrigation and for toilet flushing, respec-tively, but as low as 20–30% supported potable reuse(Denlay and Dowsett, 1994); in the UK, 89% of 300respondents agreed with the statement ‘‘I have no objectionto water recycling as long as safety is guaranteed’’ (Jeffreyand Jefferson, 2003). The collective data from these surveys(and from others, e.g. Jeffrey and Jefferson, 2003; SydneyWater, 1999) show that unfavorable responses towardreuse were related directly to the perceived degree ofcontact with the reclaimed water. Crook (2003) adds thatin the United States the public generally supports non-potable reuse, while acceptance of potable reuse isproblematic (with typically less than 50% support). Theprimary concerns of the public are costs and public healthprotection, thus uses that result in financial gains andinvolve minimal degree of contact with the reclaimed waterare favored.
Bruvold (1988) made an important distinction betweenresults from surveys dealing with what he termed ‘‘general-ized reuse uses for an undefined community, at someunspecified future time’’ and results obtained from surveysaddressing specific uses of reclaimed water, actuallyproposed for the respondents’ community in the nearfuture. Bruvold found that in the latter case a favorableattitude towards reuse was not necessarily inversely relatedto degree of contact as had been the conclusion based onthe previous, more general, surveys. It was further foundthat beyond the importance of the ‘‘degree of contact’’ therespondents were also affected by reasons of waterconservation, environmental and health issues, and costsof treatment and distribution of water. In contrast, Marks(2004), reviewing public acceptance of potable reuse,suggests that for this type of reuse the degree of contactis still the most dominant consideration. Some recent casestudies seem to strengthen Bruvold’s point, at least for usesthat do not involve direct potable reuse (i.e. drinking): Van
der Hoek et al. (1999) report on a survey performed inAmsterdam to examine public attitude toward reuse in abig housing project that was due to start a year later. In thesurvey, 97% and 80% of the public supported wastewaterreuse for toilet flushing and for clothes washing, respec-tively. Another example: Marks et al. (2003) report that all20 residents interviewed in Adelaide, where a dualdistribution system is built but not yet operational, werestrongly in favor of garden irrigation and toilet flushingwith the reclaimed water.For the third category (public attitude toward reclaimed
water where reuse schemes are already in place) there isonly limited data: Marks et al. (2003) report the results ofqualitative research performed in three operational reuse(non-potable) sites (two in Florida, one in Adelaide,Australia), where 95–100% of the residents used thereclaimed water for garden watering, in the Adelaide site100% used the water for toilet flushing, and 55% and 50%used the water for car washing in Florida (one site) andAdelaide, respectively. This variation in uses is mainly dueto structural limitations at the various sites (e.g. in theFlorida site, indoor reuse is impossible). Cost savings wassignaled out as the most important benefit of water reuse,as it was chosen by 71% of the respondents. This wasfollowed by positive effects on the environment and notwasting potable water (with 36% and 34%, respectively),25% noted the nutritional value of the reclaimed water toplants, while 20% noted satisfaction with their role inconserving water as one of the significant benefits ofreusing water.In all, 85–95% of the people in the three sites stated that
they had no concerns related to the reuse of wastewatereffluent. The few people who raised concerns said thatthese were related to contact of young children with thereclaimed water (direct or indirect), stating that childrenlike to play with water. Somewhat in contrast with theabove, when asked, about 50% of the respondents thoughtthat others may be reluctant to use reclaimed water, thesuggested reasons for which were: concerns of quality(44%), issues related to costs (26%), and the rest 30%distributed between apathy, skepticism, dislike of changeand other reasons.
Importance of dissemination of information to the public:According to the authors’ experience it is safe to say thatthe majority of water sector professionals in arid and semi-arid regions are in favor of reusing wastewater effluents(especially for non-potable reuse options). However, thedissemination of this concept to the public is sometimes adifficult task. This is due in part to the non-homogenousnature of the population consisting of groups of differentsocioeconomic backgrounds, cultures and interests. Urbanwastewater reuse projects, and in particular domestic non-potable reuse, may cause concern that under certaincircumstances can even lead to complete rejection of areuse scheme. For example: Gibson and Apostolidis (2001)explained that the Rouse Hill (Sydney, Australia) non-potable residential reuse scheme (dual distribution system)
ARTICLE IN PRESSE. Friedler et al. / Journal of Environmental Management 81 (2006) 360–370362
suffered from numerous problems originating not onlyfrom technical problems, but also from lack of consulta-tion and proper communication with the community.Crook (2003) reported that growers of edible crops in theUS believe that reclaimed water is as good as, or betterthan the irrigation water they normally use. However,although these crops (irrigated with reclaimed water) areacceptable to brokers, wholesalers and store managers,they are reluctant to advertise the source of the water dueto concerns regarding negative public perceptions.
Based on several examples from Australia, Gibson andApostolidis (2001) state that communities are extremelyvolatile on issues associated with recycling, and that publicopinion often shifts dramatically based on a small changein the information supplied. A number of large-scalewastewater reuse schemes (potable) in the USA (surfacewater augmentation, and aquifer recharge) were con-structed but never became operative due to publicopposition, very likely resulting from insufficient dissemi-nation of information to the public and/or of inappropriateand poorly managed public information campaigns (De-Sena, 1998; Hartling, 2001; Crook, 2003).
Hartling (2001) describes three main measures that ifimplemented correctly, may increase public acceptance ofwastewater reuse schemes: (1) to be transparent and revealall facts, positive and negative, about the project; (2) to talkin regular English, to use non-professional terminology,and to present the project in a clear and interesting way; (3)to have the public participate in the decision-makingprocess. Ashley et al. (2001) indicate that publicity(including advertisement in the media), education andactual inclusion of all stakeholders (politicians, experts andgeneral public) in the decision-making process are keyelements in successful design and implementation of wateror wastewater projects. Gibson and Apostolidis (2001)state that the community should be involved in all levels ofdecision making, and that the best way to involve thegeneral public and to gain its support is through successfuldemonstration projects. In this regard, Simpson (1999)reports an interesting example. In 1993, as the sewagetreatment plant was nearing its design capacity in the cityof Noosa, Australia, an option of direct potable waste-water reuse (i.e. pumping wastewater after treatment backto the water distribution system) was raised and the publicwas consulted. Consultation consisted of information daysand workshops organized by the local environmentcouncil. These resulted in a significant section of thecommunity becoming well informed, and consequentlysupportive of the potable reuse option. A following publicsurvey showed clearly that people who had attendedinformation days and public workshops were moreinformed, and thus accepted a wider range of reuse optionsthan those who had not. Eventually, the city councilrejected the option of potable reuse by one vote.
Characterization of a typical objector: When trying tocharacterize a typical objector to water reuse, two distinctreuse options have to be considered, namely: potable reuse
options (high degree of contact) and non-potable reuseones (low to medium degree of contact).
�
Potable reuse (high contact): Bruvold (1984) character-ized the typical objector to potable reuse as having a lowsocioeconomic status, being of elderly age, and havinglow awareness of water and environmental issues. Insome surveys females were found to be more opposed topotable reuse than males. Marks (2004) reviewedfindings from 11 different surveys (five in Californiaand five in the USA, UK and Australia). She also foundthat men are, in general, more receptive than women tothe notion of potable reuse; that there are contradictingand inconclusive results regarding correlation betweenage and support for potable reuse; and that highereducation tends to be associated with support. � Non-potable reuse (low to medium contact): Generallyno correlation was found between biographical char-acteristics and support for non-potable reuse options(Sydney Water, 1999; Jeffrey and Jefferson, 2003;Marks, 2004). However, Marks (2004), notes that self-employed, professional and white collar workers aremore receptive to non-potable reuse options such aslaundry and showering than other occupational groups.
Status of wastewater reuse in israel: Israel is a denselypopulated, semi-arid country suffering from a perpetual,severe water shortage. In order to cope with the waterstress, many wastewater reuse schemes, operating mainlyfor agricultural irrigation, have been introduced in the lastfour decades. The reuse projects vary in size from small,local schemes supplying 50 000m3/year, to large, regionalones that supply more than 100� 106m3/year (Friedler,2001). To date, more than 65% of the collected municipalsewage is reused for agriculture, and by the end of thedecade it is envisaged that more than 90% will be reused.As the potential of wastewater reuse for agriculturalirrigation will reach its capacity in the near future, andbecause of the clear benefits of reusing the water close towhere it is generated, urban reuse options are presentlygaining support. With respect to current public awarenessin Israel: because water reuse in Israel is implementedalmost invariably outside the cities, the exposure of mostcity inhabitants to the massive use of reclaimed water isminimal. However, common belief is that most Israelis,regardless of where they live, are highly aware of theproblem of water shortage, a much publicized problem onIsrael’s national agenda.
1.1. Research incentive
Despite the fact that a few public opinion surveys on theissue of water reuse are found in the literature, almost allwere conducted in a limited number of countries (US,Australia, Western Europe). It is likely that for the purposeof informing strategy and policy, public attitude studies arerequired in each national and sometimes sub-national
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Table 1
Reuse options in the survey: Relative weights and Average grades
Reuse category and option Relative weight
of optionaAverage gradeb
(%)
Low contact
Field crops irrigation (cotton,
fodder(
(1/3) 86
Aquifer recharge for
agricultural reuse
(1/3) 67
Orchard irrigation (1/3) 53
Medium contact
Fire fighting (1/22) 94
Use in electronics industry (1/22) 79
Cotton processing industry (1/22) 85
Use for construction of
buildings
(1/22) 93
Sidewalks landscape irrigation (1/22) 93
Air-conditioning water (1/22) 78
Offices toilet flushing+general
cleaning
(1/22) 86
Public parks irrigation (urban) (2/22) 92
Commercial car-wash (2/22) 80
Recreational lake—fishing &
boating
(2/22) 39
Private garden irrigation (3/22) 80
Domestic toilet flushing (3/22) 79
Commercial launderettes (3/22) 67
High contact
Domestic washing machine (1/7) 45
Recreational lake—swimming (1/7) 31
Vegetables (edible) irrigation (1/7) 48
Aquifer augmentation
(drinking water)
(2/7) 20
Use in preserved food industry (2/7) 24
a
E. Friedler et al. / Journal of Environmental Management 81 (2006) 360–370 363
context, because of the large variation in culture, climate,water availability, economy, etc. Such variability makes thetransferability of specific findings and conclusions from onecountry to another somewhat problematic. An interestingexample that emphasizes this point is a survey that wasconducted in Doha, Qatar (Ahmad, 1991), that revealedthat in stark contrast to most results obtained elsewhere, alarge percentage of the respondents opposed even low tomedium contact reuse options, such as farming (92%),lawn and garden irrigation (50%), car washing (50%), andindustrial reuse (88%).
1.2. Research goals
From the combined experience gathered in the last threedecades worldwide it is clear that a successful reuse projectshould be preceded by a successful information dissemina-tion campaign that addresses the concerns of the community,and also includes active participation of members of thegeneral public. In order to gain a glimpse of the publicapproach, such a campaign often starts by conducting apublic attitudes survey. Jeffrey and Jefferson (2003) state thatsimply asking the public about reuse options ‘‘can exposeattitudes and motivations which inform system design as wellas application’’. Such a survey has never been conducted inthe urban sector in Israel despite the country’s long andsuccessful water reuse experience. This paper addresses theissue of public support/objection to various types of waste-water reuse. This was established by an opinion survey usinga representative sample of the general un-exposed Israelipublic (prior to the introduction of a specific publicity/educational program). The main research goals were:
The relative weights indicate the relative importance attached by the
authors to each application.bThe grade is a simple average of all answers given by the participants to
(1)each reuse option, normalized between 0% and 100%.
To estimate the level of opposition to and support forvarious wastewater reuse options, with particular atten-tion to reuse options within the urban environment.
(2)
To reveal critical issues which should be specificallyaddressed by public information campaigns (such asissues that concern the public, perceptions of variousreuse options, etc.). In particular, we were interested inestablishing the main concerns of the public regardingreuse options we defined as ‘‘medium contact’’ (Table1), that are, in our opinion, realistic for urban reuse inIsrael in the near future.(3)
To assess the socioeconomic characteristics of a typical‘‘objector’’ to wastewater reuse (if such characteristicsexist) and compare them with Bruvold’s findings andmore recent studies. Such characterization is expectedto assist in preparing a public information campaign.2. Methods
2.1. Survey methodology
A multiple choice administered questionnaire survey wasconducted on the urban population of Haifa, which is the
third largest city in Israel (about 270 000 inhabitants,ICBS, 2003). Based on socioeconomic parameters, the citywas divided (non-randomly) into five neighborhood-basedsections. The number of people selected in each section wasdetermined by its relative population size. Streets in everysection were randomly selected. In each street threeresidential buildings (consisting of four flats at least) werearbitrarily selected. Inhabitants of these selected buildingswere asked to complete the survey questionnaire, with atotal of four people per street. These were the first onesagreeing to participate in the survey in the chosenbuildings, with a maximum of two persons per building.When the volunteers failed to find four persons agreeing toparticipate (from the pre-selected buildings), they ran-domly selected another building in the same street andrepeated the above process.Four students delivered and collected the questionnaires.
They stayed with the participants while they were fillingthe questionnaire. They clarified the terms used in thequestionnaires (when asked), without revealing any
ARTICLE IN PRESSE. Friedler et al. / Journal of Environmental Management 81 (2006) 360–370364
personal opinion. The participants were assured ofanonymity (no identifying personal details were collected).
2.2. The questionnaire
Twenty one reuse options were considered in the survey(Table 1). These were divided into three categories:
(1)
Low contact: Reuse options that have only indirect linkto the urban population (all three options in this groupare presently implemented in Israel on a large scale).These reuse options are implemented in rural areas anddo not involve any direct contact (intentional orunintentional) of the reclaimed water with city dwellers.(2)
Medium contact: Options that are implemented in closeproximity to urban population, but that do not involveintentional contact with humans (none of these optionsare presently implemented on a large scale in Israel).These reuse options are generally implemented withinor close to the urban environment, and may involveunintentional direct contact with the reclaimed water.(3)
High contact: Options that involve intensive contactwith the urban population, e.g.: intentional bodycontact, indirect drinking. None of these options isimplemented in Israel.The questionnaires consisted of general instructions, ashort explanation of the topic of the survey, and threesections to be filled in by the participant:
(1)
Biographic background: Five variables defined thebiographical background of each interviewee:(i) Gender:(ii) Age: 18–30 years old, 30–40, 41–50, 51–60, above60 years of age.
(iii) Education: Less than 12 years, 12 years (completehigh school education), more than 12 years.
(iv) Marital status: Married, Married+children, Sin-gle, Divorced, Other.
(v) Income level: Below average, Average, Aboveaverage.
(2)
Reuse options: Participants were asked to mark each ofthe 21 reuse option on a scale from zero to four(0 ¼ strongly opposed; 1 ¼ opposed; 2 ¼ indifferent;3 ¼ supportive, 4 ¼ strongly supportive).(3)
Environmental perceptions: Participants were asked tograde (in a manner similar to the above) eight questionsthat were used to identify their perceptions on waterand environmental issues: (i). Their opinion on the stateof the water sector in Israel. (ii) Their opinion regardingthe ability of current wastewater technologies toproduce effluents suitable for the proposed wastewaterreuse options. (iii) Their opinion regarding whether thepublic in Haifa would support the described reuseoptions. (iv). The extent of water resources pollution inIsrael. (v). The extent of economic benefits to the publicfrom urban wastewater reuse in Haifa. (vi). The extentof the health risk associated with urban reuse. (vii) Theextent of their belief that the relevant authoritiesare capable of maintaining a high effluent quality.(viii) The extent that the individual will gain economic-ally from the implementation of reuse schemes inthe city.
(4)
Reasons for support: Participants who identified them-selves as supporters of wastewater reuse were asked tograde (in the same manner as before) how each of thefollowing reasons affected their support: (1) urbanwastewater reuse would reduce infrastructure costs andimprove the economy; (2) wastewater reuse is good forthe environment; (3) wastewater reuse will save water;(4) wastewater reuse would minimize Israel’s depen-dency on imported water.2.3. Data analysis
In order to grade an individual reuse option, a simpleaverage of all the answers regarding that option was used,normalized for a scale of 0–100, where 0 is completerejection and 100 is complete acceptance.Weighted grades were used in attempting to correlate
between level of support and biographical characteristics,between level of support and personal opinion/beliefs, andto analyze differences between the three reuse categories(low, medium and high contact). The weighted grades werecalculated in the following manner:First, each reuse option received a relative weighting
factor within its category (shown in Table 1), proportionalto its impact or the probability of personal contact(intentional or unintentional) as perceived by the authors(the sum of all weighting factors in each category is 1). Forexample:
�
Low contact: All three reuse options received the sameweighting factor (1/3), since their impact and probabilityof personal contact were assessed to be about the same. � Medium contact: The various options were graded by theauthors according to their possible contact with thepopulation, but also taking into consideration otherfactors. For example, the option of reuse for office toiletflushing received a weighting factor of 1/22, while reusefor domestic toilet flushing received a factor of 3/22. Thedifference between the weighting factors of these twooptions (which at a first glance look identical) emanatesfrom the different probabilities of unintentional crossconnections between potable water and reclaimed water.Office buildings are usually centrally maintained, whilein many cases the tenants/owners themselves areresponsible for the maintenance of their flats. Thus,the probability of mistaken cross connections occurringin residential flats (by either the owner/tenant or by anunder qualified plumber) is higher than the probabilityof cross connections occurring in centrally maintainedbuildings.
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Tab
Ag
Ag
Ra
18–
31–
41–
51–
46
a
(ICb
c
d
E. Friedler et al. / Journal of Environmental Management 81 (2006) 360–370 365
Following a similar logic irrigation of urban publicparks received a weighting factor of 2/22, whileirrigation of private gardens received a factor of 3/22.This stems from a higher possible contact in the latterreuse option, e.g.: kids playing with the water, irrigationby a garden hose, misusing the reused water (using themfor uses they were not intended for), and higher risk ofcross connections (Marks et al., 2003).
� High contact: Aquifer augmentation for potable reusereceived a weighting factor of 2/7, while reuse in thedomestic washing machine has a factor of 1/7. This isdue to the fact that the impact (real or perceived) of thefirst option was thought to be higher than that of thelatter one.
The weighted grade of each reuse category (i.e. low,medium, and high contact) in each questionnaire wascalculated using
Gc ¼ 100Xn
i¼1
SiW i
4Pn
i¼1W i
� �, (1)
where Gc is the weighted grade of a reuse category in aparticular questionnaire, on a scale of 0–100% (highergrade indicates higher support). Si the Score of a particularreuse option, as given by participant i (0—4, where 0 iscomplete refusal and 4 stands for full support). Wi theweighting factor of each reuse option within its reusecategory. n is the number of reuse options in each reusecategory (low contact ¼ 3; medium contact ¼ 13; highcontact ¼ 5).
The value ‘‘4’’ which appears in the denominator of Eq.(1) turns the weighted grade (the expression within thebrackets) to a proportion ranging from 0 to 1. Multiplyingthis proportion by 100 turns the weighted grade of eachcategory to a percent-based number. For example: If aparticipant gave all reuse options in one category a score offour, than the proportional grade of the category would be1, and the weighted grade 100%. On the other hand, ascore of two given by a participant to all reuse optionswithin a certain category will result in a weighted grade of
le 2
e distribution and education level of survey participants
e Education Marital stat
nge Proportiona (%) Education Proportiona,b (%)
30 36.3(29.7) o 12 years 2.4 (17) Single
40 9.8(16.4) Married
50 16.8(17.5) 12 years 36.6(33) Married+c
60 11.7(16.8) (high school) Divorced
1 23.8(19.7) 412 years 59.4(43) Other
Values in brackets indicate data distribution of the adult population in
BS, 2003).
Four participants (1.6%) preferred not to reveal their education level.
Eight participants (3.1%) preferred not to reveal their income level.
Average monthly gross income in Israel in 2003 NIS 6972 (ca US$ 1550).
50%. Following this rationale, a weighted grade above56% was considered supportive, below 44% the individualwas considered opposed, and between 44% and 56% wasconsidered as having no firm opinion regarding the notionof wastewater reuse.
3. Results and discussion
A total of 256 people, 105 males (41.4%) and 150females (58.6%), completed the questionnaire (in onequestionnaire the gender was not specified). The responserate was around 50% (i.e. on average, for each person whoagreed to participate, one refused). The proportion of menparticipants was lower than their proportion in thepopulation (41.4% vs. 48% in the Haifa population; ICBS,2003). A summary of the participants’ biographicalcharacteristics is given in Table 2. The refusal proportionsin the lower education level group were somewhat higherthan the refusal rates in the higher education level. Thus,the higher education level group had higher representationthan its proportion in the general population (59.4% in thesample vs. 43% in the general population). This may havecaused a slight bias in the results, as highly educated peopletend to be better informed on environmental and socialissues, although in this work no correlation was foundbetween level of education and support for water reuse.The age distribution of the participants agreed well withthe distribution of the Haifa population, with some overrepresentation of the 18–30 year old age group. The incomelevel of the sample also reflected the distribution of theincome of the Haifa population, with a very small overrepresentation of the low-income level.The proportions of participants that supported, were
indifferent, or opposed each of the various reuse optionsare shown in Fig. 1. The options in Fig. 1 were groupedinto low, medium and high contact reuse options as definedby the authors. In parallel, Table 1 lists the average gradethat was given by all of the participants to each of theoptions in the survey. The average grade is the sum of allthe results regarding a particular option divided by the
us Gross income
Proportiona (%) Income level [US$/month] Proportiona,c
(%)
31.8(29.8) o 1440 (o Average) 42.2(45.5)
11:0
41:6
�ð56:5Þhildren 1440–1660 ( ¼ Averaged) 37.5(34.5)
8.2(6.6)
7.5(7.1) 41660 (4Average) 17.2(19.0)
Haifa (age) and in Israel (education, marital status & gross income)
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Fig. 1. Proportion of the participants supportive, indifferent and opposed to the 21 reuse options considered in the survey.
E. Friedler et al. / Journal of Environmental Management 81 (2006) 360–370366
number of participants, normalized for a scale from 0%(complete rejection) to 100% (absolute support).
Both Fig. 1 and Table 1 show that, by and large, reuseoptions that were perceived by the public as low or mediumcontact, received high support. For example, reuse optionsperceived by most participants as ‘‘low contact’’ receivedthe support of over 90% of the participants (e.g. firefighting (95.7%), public park irrigation (95.7%), andsidewalk landscaping (94.5%)). On the other hand, reuseoptions believed to have a higher degree of contact receivedrelatively low support (e.g. only 20.3% of the participantswould swim in a lake mixed with reused wastewater, while65.5% would not, and only 10.9% of the participants werefor the option of potable aquifer augmentation while79.9% rejected it). These findings (high support for lowcontact reuse) agree well with those of Bruvold (1984),Crook et al. (1994), and Denlay and Dowsett (1994). Therelatively high support for the options defined in the workas medium contact agrees well with the findings of Bruvold(1988), Sydney Water (1999) and Marks (2004). Theseincluded high support for reuse options which have apotential for close contact with the public, such as privategardening (78.1% support), home WC flushing (83.2%),and car washing (75.4%).
Interestingly, the results also showed that the publicperception of low contact reuse options was somewhatdifferent from that of the authors. This is best demon-strated in the case of aquifer recharge for agriculturalirrigation, and irrigation of peel-fruit trees (orchards).
Both, to our surprise, received relatively low support(61.7% and 48.8% of the participants supported them,respectively) and relatively high opposition (27.0% and39.5% of the participants). This was particularly unex-pected as these reuse options have been largely practiced inIsrael for over 30 years, without any negative effects.Orchard irrigation is indeed a low contact reuse option, asthe irrigated water (normally by drip irrigation) hardlycomes into any contact with the fruit. Further, the fruit ispeeled before it is eaten. However, this incongruity is animportant point that should be considered when planningreuse schemes: the attitude and perception of the publicmay differ from ‘‘conventional logic’’ of experts.Using Eq. (1), the weighted grades of the three reuse
types were calculated for each filled questionnaire, then theparticipants’ perception towards low, medium and highcontact reuse types was analyzed by a histogram-typedistribution (Fig. 2A–C, respectively). As expected, ingeneral, the higher the contact level the lower was thesupport for the reuse option. Other interesting observa-tions include:
�
The average grade of low contact reuse was 72.9(Fig. 2A), a grade that can be considered as supportiveof the reuse options presented under this category,although less supportive than expected. The highestproportion of the participants (30.5%) gave low contactreuse a weighted grade of 91–100, i.e. unconditionalsupport, while the second highest proportion of
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0
5
10
15
20
25
30
0
5
10
15
20
25
30
35
0-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 81-90 91-100
0-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 81-90 91-100
0-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 81-90 91-100
Avg Grade - 72.9STD - 24.2Median - 80.0
0
5
10
15
20
25Avg Grade - 356STD - 24.2Median - 30.0
Avg Grade - 82.6STD - 16.2Median - 90
Prop
ortio
n (%
)Pr
opor
tion
(%)
Prop
ortio
n (%
)
Low contact
Medium contact
High contact
(A)
(B)
(C)
Fig. 2. Histogram distribution of the weighted grade frequencies for low,
medium and high contact reuse option A ¼ low contact, B ¼ medium
contact, and C ¼ high contact.
100
Support Indfferent Opposed
E. Friedler et al. / Journal of Environmental Management 81 (2006) 360–370 367
participants (16.4%) gave low contact reuse a gradebetween 51 and 60, that can be considered as neithersupport nor oppose. The discrepancy apparently stemsfrom the different perceptions of the respondents andthe authors regarding low contact reuse options (asexplained above).
�0
20
40
60
80
Low Contact Medium Contact High Contact
Pro
port
ion
(%)
Participants expressed very high support towardsmedium contact reuse (Fig. 2B) with an average gradeof 82.6 (median ¼ 90). The highest proportion of thepublic (28.1%) gave medium contact reuse a weightedgrade of 91–100 (i.e. complete support), and over 50%of the participants had a weighted grade of above 80%.The frequency histogram of the weighted grades ofmedium contact reuse is skewed to the right, as indicatedby the very small number of people strongly objecting tothe concept of medium contact reuse (only 3.9% givingweighted grades of 40 or less (with none of theparticipants giving a weighted grade of less than 21).
Fig. 3. Proportion of participants defined as supportive, no opinion, and
�opposed to low, medium and high contact reuse options (Oppo-
sed ¼ weighted grade 0–44, No opinion ¼ weighted grade 46–56,
Supportive ¼ weighted grade 56–100).
Participants generally objected to the notion of highcontact reuse (Fig. 2C). The average weighted grade was35.5 and the median grade was even lower (30.0). Only
19.5% of participants gave high contact reuse aweighted grade of 60 or more.
Lumping the weighted grades into three categories:(Supporters—giving weighted grades of 56–100, Having noopinion—giving weighted grades of 44–56; Opposed—giving weighted grades of 0–44) enables to generallyquantify the support/objection proportions of the public(Fig. 3). The average population support as reflected by thesurvey was 71%, 90% and 16% for low, medium and highcontact reuse types, respectively. The opposition to thesereuse types was 21%, 4% and 76%, respectively. Thereasons for this are discussed above.Most of the questions in the survey and the statistical
correlations presented in the paper address reuse optionsdefined by the authors as medium contact reuse type. Therationale for this was two fold: On the one hand, thepremise was that the public would generally support lowcontact reuse options, which are already implemented on alarge scale in Israel (especially options related to agricul-tural irrigation). On the other hand, there are no plans toimplement high contact reuse projects in the foreseeablefuture in Israel, and besides, it was expected that highcontact reuse options would be largely rejected by thepublic. Therefore, public perceptions towards mediumcontact reuse options deserved in our opinion a morecareful examination, particularly as these appear to be thenext practical alternatives to be implemented. The discus-sion below analyzes the results pertaining to mediumcontact reuse options.Table 3 presents correlation analysis between the level of
support of the medium contact options and personal andenvironmental beliefs. Highly significant negative correla-tion was found between the belief that wastewater reusecan cause negative health effects and the level of support ofmedium contact reuse (Spearman Rank Correlation test[SRC]; ao0:01, correlation coefficient ¼ �0.465). Positivecorrelation was found between perception of public
ARTICLE IN PRESS
Table 3
Medium contact reuse: Statistical analysis of opinion distribution as a function of personal beliefs/perceptions (Statistical test–Spearman rank-order
correlation)
Belief Oppose (%)a No opinion (%)a Support (%)a Total no. Correlation coefficient Significance b(a)
Awareness to water & environmental issues
Aware 3.1 5.5 82.8 227
Medium awareness 0.4 0 5.5 15 0.048 0.442
Not aware 0.8 0 2.0 14
Appropriate technology
Technology exists 1.2 1.2 26.3 71
No opinion 2.4 3.1 38.0 111 0.071 0.261
No appropriate technology exists 0.8 0.8 26.3 74
Economic benefits to the city
Economical benefit 2.3 3.1 67.2 186
No opinion 0 2.0 12.5 37 0.225 o0.01
Economical decline 2.0 0.4 10.5 33
Effects on public health
No adverse health effects 2.7 2.4 11.8 43
No opinion 0.4 2.0 29.8 82 �0.465 o0.01
Adverse health effect will occur 0.8 1.2 49.0 130
Public opinion
Public will support 0.4 2.5 54.7 136
No opinion 0 1.7 15.7 41 0.261 o0.01
Public will oppose 3.4 0.8 20.8 59
Individual economic gain
Individual gain is an incentive 1.2 1.6 66.0 177
No opinion 0.4 1.2 7.0 22 0.375 o0.01
Individual gain not an incentive 2.7 2.7 17.2 58
Trust in authorities
Trust 1.2 2.0 29.3 83
No opinion 0.8 1.2 14.8 43 0.03 0.958
No trust 2.3 2.3 46.1 130
aOppose—weighted grade 0–44, No opinion—weighted grade 44–56, Support—weighted grade 56–100.bValues in bold, are statistically significant (ao0:05).
E. Friedler et al. / Journal of Environmental Management 81 (2006) 360–370368
opinion and personal support of medium contact reuse, i.e.the higher the belief of a person that the public supports areuse scheme, the higher the likelihood of the same personto support the scheme (SRC test; ao0:01, correlationcoefficient ¼ 0.261). This finding should be consideredwith some caution, because a supportive person maybelieve that others share the same views. Medium strengthcorrelation was found between the belief that the citywould benefit economically from reuse projects, and thelevel of support, and a strong correlation was foundbetween the belief that the individual will personally profitfrom the implementation of reuse schemes and level ofsupport. These results conform well to a number of studiesthat found a clear correlation between economic gain andsupport for water reuse (Marks et al., 2003). Surprisingly,no correlation was found between personal awareness ofwater and environmental issues and support of reuse. Thiscan be perhaps explained by the fact that Israel suffersfrom water scarcity and thus this issue appears in the mediafrequently, and there are very few people who are notaware of the problem (as reflected by the fact that only4.3% of participants declared themselves completely
unaware), and even these are probably aware to the issueas reflected by their relative high support (60%). Further-more, no correlation was established between the beliefthat an appropriate water treatment technology exists andthe level of support, and between the trust the public has inthe authorities and the level of support. It appears that thepublic, that in principal doubts the competence of theauthorities and their ability to supply adequate effluents,strongly believes that medium contact reuse options shouldbe implemented, notwithstanding.Table 4 shows the results of correlation analysis carried
out between biographical characteristics and support ofmedium contact reuse. No correlation was found betweenany of the biographical classes and level of support. Thesurvey showed a weak, but not significant correlationbetween level of support and age (Pearson; P ¼ 0:387).This contradicts some other works (non-potable reuse) thatfound no correlation between age and degree of support.No correlation was also found to exist between gender andlevel of support (t test; P ¼ 0:875), a finding that falls inlinewith others who worked on non-potable reuse (Jeffrey andJefferson, 2003) and contradicts reports on potable reuse
ARTICLE IN PRESS
Table 4
Correlation between biographical classification and level of support of medium contact reuse options
Independent variable Type Statistical test Results Conclusion
Gender Dichotomic, based on two
independent groups
Independent samples t test P ¼ 0:87540:05 No correlation
Marital status Categorial (5 categories) One-way Anova P ¼ 0:56340:05 No correlation
Families with and without
young children
Dichotomic Independent samples t test P ¼ 0:86740:05 No correlation
Age Continuous, quantitative and
normal
Pearson correlation P ¼ 0:38740:05 Weak correlation
(0.055), not significant
Education Categorial (3 categories) One-way Anova P ¼ 0:12240:05 No correlation
Income Categorial (3 categories) One-way Anova P ¼ 0:07440:05 No correlation
E. Friedler et al. / Journal of Environmental Management 81 (2006) 360–370 369
(Bruvold, 1984; Marks, 2004). Furthermore, no correlation(One way Anova, P ¼ 0:122) was found to exist betweeneducation level or income level and support of mediumcontact reuse. As shown in Table 2, an over representationof highly educated individuals was observed in the survey.Normally, one would expect that the high-income levelcategory would also be over represented. However, thiswas not observed. Such abnormality is often associatedwith an immigrant society, in which highly educated peopleare sometimes not employed in their original professions(during the 1990s a large number of immigrants arrived inHaifa from the former Soviet Union). This may explain thefact that no correlation was found between income leveland support.
No correlation was also established between maritalstatus and support of medium contact reuse options.Moreover, married individuals having young children athome were not found to be less supportive of water reuseschemes than ones with no children at home (t test,P ¼ 0:867).
3.1. Grading the reasons for support
Participants who identified themselves as supporters ofwastewater reuse in general (without specific address tolow, medium or high contact reuse options) were asked tograde the reasons that affected their support (see discussionin Methods section).
The results were first analyzed using the Friedman non-parametric test, which showed that there was a significantdifference (Po0:000) between the ways that these partici-pants perceived the four questions. Subsequently, theWilcoxon Signed Ranks Test was used to grade the relativeimportance given to each of the reasons by the public. Thetest showed that the most important reason for supportwas ‘‘Water Saving’’ (Po0:000 against all other reasons),followed by ‘‘Minimization of Amount of Water Im-ported’’ (po0:001 against ‘‘Infrastructure Cost Saving’’).No significant difference could be established between‘‘Infrastructure Cost Saving’’ and ‘‘Environmental Im-provement’’, although these were also perceived by thepublic as important reasons for supporting wastewaterreuse.
4. Conclusions
Generally speaking, the survey shows a considerablesupport for the notion of wastewater reuse schemes. Morespecifically, options that were defined in the study asmedium contact found very high support, includingsupport for reuse options that have considerable contactwith individuals, such as private gardening, home WCflushing, and commercial car washing. As expected, highercontact options such as aquifer augmentation and use inthe preserved food industry received much lower support.The survey points to several important issues that have
to be considered before a new wastewater reuse scheme isto be implemented:
�
Public perception of the degree of contact of variousreuse options may differ from that of professionals. Thismay lead to support of medium contact options andrejection of low contact ones. For example, orchardirrigation with reused water that has been implementedin Israel from the 1970s without any adverse healtheffects was, despite this fact, completely rejected by39.5% of the survey participants. It is reasonable that acarefully planned public information campaign cansucceed in changing the opposition to this reuse option,as there is no real health hazard associated with thispractice. This example stresses the importance ofunderstanding concepts prevailing in the public andunveiling their origins. � No correlation was found in the current survey betweenbiographical characteristics (age, gender, marital status,having young children at home, education level, andincome level) and level of support for medium contactreuse options. Nevertheless, in contrast to results fromthe US, and although not proved to be statisticallysignificant in this research, older people in Israel may bemore supportive than youngsters. Thus, campaignsmight consider concentrating on the younger fractionof the adult population.
� Possible health risks are of major importance. Peoplewho associate water reuse with substantial healthhazards are bound to object to medium contact reuseoptions. This negative correlation contradicts other
ARTICLE IN PRESSE. Friedler et al. / Journal of Environmental Management 81 (2006) 360–370370
studies that found that health effects do not seem to playa role when medium contact reuse options are consid-ered. Consequently, one of the major goals of a publiccampaign should be to clarify this subject and fullyinform the public of the degree of health risk associatedwith each reuse option, and the means that will be takento minimize it. Based on experience from Australia, thebest way to try and convince the public on this crucialsubject is by constructing and operating demonstrationsites a few years before full-scale implementation, andinvite the public to visit, in order to alleviate fears.
� In parallel to demonstration sites, the survey reveals theimportance of generating a general positive publicopinion towards water reuse projects, and publicizingthese as much as possible, as this seems to enhance thesupport of individuals towards such projects. However,this finding should be treated with caution, since peoplewho support water reuse may think that the generalpublic supports it too.
� The results of the survey suggest that public campaignsshould emphasize the potential economic benefits of awater reuse project to the city in general and to theindividual end user in particular.
� The survey results may have been slightly biasedtowards higher support of wastewater reuse because ofan overrepresentation of highly educated people in thesampled population. However, no such correlation wasfound in the present study.
� The fact that wastewater reuse saves fresh water wasperceived by participants who identified themselves asbeing generally supportive of water reuse, as the mostimportant reason affecting their support. This reasonwas followed by minimization of dependency onimported water and economical and environmentalimprovement (the latter two received the same grade).Generally speaking, all four reasons should be empha-sized in a public campaign, as all of them are apparentlyimportant to the public.
Acknowledgment
The financial support of the Grand Water ResearchInstitute, Technion, is greatly appreciated.
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